Here’s the text of ACR-99, which looks like a non-binding resolution (at least for now):
I suspect anything more would fail constitutionally but maybe it’s only a matter of time.
Legal vs. illegal, I suppose, comes down to the predilections of a bunch of lawyers wearing black robes living in (or near) Washington, D.C.
I’m reminded of this, which was five years ago and in the great state of Texas:
The city of Houston has issued subpoenas demanding a group of pastors turn over any sermons dealing with homosexuality, gender identity or Annise Parker, the city’s first openly lesbian mayor. And those ministers who fail to comply could be held in contempt of court.